Maternal aggression in Wistar rats: effect of 5-HT2A/2C receptor agonist and antagonist microinjected into the dorsal periaqueductal gray matter and medial septum

Abstract

The objective of the present study was to assess the role of the 5-HT 2A/2C receptor at two specific brain sites, i.e., the dorsal periaqueductal gray matter (DPAG) and the medial septal (MS) area, in maternal aggressive behavior after the microinjection of either a 5-HT 2A/2C receptor agonist or antagonist. Female Wistar rats were microinjected on the 7th postpartum day with the selective agonist α-methyl-5-hydroxytryptamine maleate (5-HT 2A/2C ) or the antagonist 5-HT 2A/2C , ketanserin. The agonist was injected into the DPAG at 0.2 (N = 9), 0.5 (N = 10), and 1.0 µg/0.2 µl (N = 9), and the antagonist was injected at 1.0 µg/0.2 µl (N = 9). The agonist was injected into the medial septal area (MS) at 0.2 (N = 9), 0.5 (N = 7), and 1.0 µg/0.2 µl (N = 6) and the antagonist was injected at 1.0 µg/ 0.2 µl (N = 5). For the control, saline was injected into the DPAG (N = 7) and the MS (N = 12). Both areas are related to aggressive behavior and contain a high density of 5-HT receptors. Nonaggressive behaviors such as horizontal locomotion (walking) and social investigation and aggressive behaviors such as lateral threat (aggressive posture), attacks (frontal and lateral), and biting the intruder were analyzed when a male intruder was placed into the female resident's cage. For each brain area studied, the frequency of the behaviors was compared among the various treatments by analysis of variance. The results showed a decrease in maternal aggressive behavior (number of bites directed at the intruder) after microinjection of the agonist at 0.2 and 1.0 µg/0.2 µl (1.6 ± 0.7 and 0.9 ± 0.3) into the DPAG compared to the saline group (5.5 ± 1.1). There was no dose-response relationship with the agonist. The present findings suggest that the 5-HT 2A/2C receptor agonist has an inhibitory effect on maternal aggressive behavior when microinjected into the DPAG and no effect when microinjected into the MS. Ketanserin (1.0 µg/0.2 µl) decreased locomotion when microinjected into the DPAG and MS, but did not affect aggressive behavior. We interpret these findings as evidence for a specific role of 5-HT 2A/2C receptors in the DPAG in the inhibition of female aggressive behavior, dissociated from those on motor activity.

The effect of 5-HT2a/2c receptor agonist microinjected into central amygdaloid nucleus and median preoptic area on maternal aggressive behavior in rats

“…11 Although binding studies found a higher density of these receptors in limbic areas, it is interesting to note that α-Methyl-5-hydroxytryptamine maleate, the 5-HT 2A/2C receptor agonist, is more effective in reducing the aggressive behavior in mesencephalic rather than in diencephalic or telencephalic areas.…”

Association of 5-HT2A (A-1438G) receptor genotypes with the debut of coronary artery disease and personal anxiety

“…На настоящий момент известно, что генотипы 5-HT2A связаны с депрессией [14,[27][28][29]35], тревогой [65,72], агрессивно-импульсивными чертами личности [6,25,36,45,46,54,55,59,61,62,64,66], сокращением гладкомышечных сосудов [19,38,42], антитромботиче-ской активностью [5,31,42,47], воспалительными реак-циями артерий [18,26,44,74]. Все вышеописанные про-цессы связаны с патогенезом ИБС [3], вследствие этого мы решили изучить связь вариантов гена 5-HT2A (А-1438G) с дебютом ИБС.…”

“…Имеется множество сведений о том, что 5-HT2A-рецептор участвует в формировании агрессивно-импуль-сивных черт [6,25,32,36,45,54,55,59,61,62,64,66]. Су-ществуют исследования, которые эту связь не обнаружи-ли [10,17].…”

Genetics of Recidivistic Violent Behavior: A Review

“…Agents that affect these neurochemicals are known to cause serious side effects and hence the limitation of their usefulness in aggression 59 .…”